Antioxidant



Patented Nov. 21, 1939 Q 2,180,666

UNITED STATES PATENT OFFICE Albert M. Clifford, Stow, Ohio, assignor to Wingfoot Corporation, Wilmington, DeL, a corporation of Delaware No Drawing. Application September 29, 1934,

Serial No. 746,268

15 Claims. ((3118-50) This invention relates to the treatment of rubcumidine, alpha naphthylamine, beta naphthylber and the like for the purpose of improving amine, alpha methyl beta naphthylamine, amino the age resisting qualities of the same and, more diphenyl amine, p p diamino diphenyl methane,

particularly, to new and improved age resisters p p diarnino ditolyl methane, p-amino benzyl p, or antioxidants suitable to be used with rubber aniline, diamino diphenyl disulphide, ammo b1- 5 to increase the lasting qualities thereof. ph ny amino p t n -diam 0 ph n l The new age resisters or antioxidants comprise naphthyl ether, and other primary aromatic the reaction products of aliphatic alcohols and amines primary aromatic amines, a catalyst ordinarily The reaction leadin to the formation of t being used to promote the reaction. The reaction desired products is Ordinarily carried on in an mass resulting from the interaction of a given autoclave, the selected proportions of alcohol and alcohol and a given amine may be used as such, e being ea in t e p ence of a Ca y without separation of the ingredients, as an-antisuch as Z c Chloride, u m C o de OI t oxidant by direct incorporation in a rubber mix, tetra chloride, for 7 130 rs a C- by applying the same t the surface of th bb r, Maintenance of these conditions is productive of 15 Orin any other suitable manner Reaction proddesirable reaction products. Molar proportions 15 ucts of two or more alcohols on a given amine or of ol and amine give d lt but t es of two or more amines n given ,1e h 1, or proportionsmay be varied within limits and still of a plurality of alcohols'on a plurality of amines, give a Satisfactory product may also be used, As specific illustrations of the manner in which The reaction mass i complex in nature d the antioxidant mixtures are obtained, the fol- 20 contains a number of different compounds, some loWihg are given;

'or all of these apparently accounting for the vEzt'a'mzalel utility of the reaction product. Thus in the 3 V mols each of methanol, aniline and. zinc igfi gf fg g fi W111 be found, m the mass chloride are autoclaved for 7 hours at a tem- 25 p s e ype perature of 280-290 C. The black tarry reaction R NH mass is then treated with'NaOH and the resulting oil separated and subjected to distillation under reduced "pressure. The portion of the product 'Dependmg on the empmyed having a boiling point between 204-220c. under 30 iecting the reaction, other products may also be 45 mm pressure the same being. anon at room formed namely: temperaturais used as an antioxidant. BONE-11, RONHO, R NH R, Example 2 and still other compounds of the tertiary amine 3 mols each of aniline, normal butyl alcohol yp The reactions are also p ied by the and zinc chloride are heated for 7 hours in an formation O high boiling nitrogen. Containing autoclave in the same manner as in the foregoing compounds of unknown nature.- example. The oil liberated from the reaction Among the alcohols which may thus be reacted mass by treatment with20% NaOI-I i f t 40 W h a es to v the products and COmDOUIId-S ated under reduced pressure and the higher boil- 40 v of the invention may be mentioned the following: ing fra tion, having a boiling point between e y and yl alcohols, normal propyl a d 130-170 C. at 5 mm. pressure, isused in rubber. iso propyl alcohols, normal butyl, isobutyl, sec- 11-, is pale straw-colored 1 ondary butyl and tertiary butyl alcohols, amyl E 3 and iso amyl alcohols, cyclohexanol and methyl mmp e 45 cyclohexanol, hexyl, heptyl, octyl, nonyl, decyl, A mixture of 286 parts of alpha naphthylamine, hexadecyl, octadecyl alcohols, and others. 300 parts of isopropyl alcohol and 5.9 parts of Any one or more of these alcohols, and similar SnCli are heated for 9 hours at 290 C. The alcohols, may be reacted with one or more of the reaction product is distilled and the fraction hav- 5 following amines: aniline, toluidine, xylidine, -ing a boiling point range of l90245 C. at 55 mm.

pressure and amounting to,205 parts was used as an antioxidant,

The reaction products thus obtained were tested in rubber by incorporation in a stock having the following composition:

A low temperature ageing test employing the above mentioned stock gave the following results:

Original Aged Per- Oure cent w Tens. Elong. 500% 700% Tens. Elong. 500% 700% inc.

METHYL ALCOHOL+ANILINE BUTYL ALOOHOL+ANILINE ISOPROPYL ALCOHOL+ALPHA NAPHTHYLAMINE Parts Smoked sheet; 100

Zinc oxide 92.5 Carbon black .6

Sulphur 3.5 Diphenylguanidine .7 Antioxidant 5.0

Cured strips of the foregoing composition, but

varying in the particular antioxidant used, were aged in an air bomb at 114 C. for 7 hours at pounds pressure per square inch. The following data was obtained:

Orignal Aged Cure Tens. Elong. 300% 500% Tens. Elong. 300% 500% METHYL ALCOHOL+ANILINE BUTYL ALCOHOL+AN1LINE 55 2s5 190 700 22 7o 62 625 15 36 so 205 680 26 s2 84 650 1s 4s 70 212 640 32 100 82 575 25 59 ISOPROPYL ALOOHOL+ALPHA NAPHTHYLAMINE 35/285... 202 680 s0 s9 89 650 20 4s 50 218 550 as 90 580 30 e1 70 238 640 43 96 540 as 83 Here, again, the physical properties of the aged strips compare very favorably with the properties of the specimens before ageing.

It is apparent, then, that the composite products herein disclosed and described are valuable as age resisters in rubber, counteracting, as they do, the effects of heat, light and oxygen and also imparting other desirable qualities such as increased resistance to deterioration resulting from flexing. The composite products generally possess a lower melting point than the separate components thereof to which may be attributed the antioxidant effect of the mass, and the composite product therefore disperses more readily in rubber during processing. It has also been found that these complex reaction products show less tendency to bloom than do individual compounds when used in rubber, the reason for this being, perhaps, that crystals are less likely to form from such mixtures.

The term rubber, as used, includes rubber, synthetic rubber, latex, guayule, gutta percha, balata, rubber isomers and rubber conversion products and similar materials.

While preferred embodiments of the invention have been set forth in the foregoing description, the invention is not limited thereto but only by the appended claims which are intended to include all features of patentable novelty residing in the invention.

What I claim is:

1. The process of preserving rubber which comprises treating the-same with a composite 1 product obtained by causing a primary aromatic amine to react with a saturated monohydric aliphatic. hydrocarbon alcohol in approximately molar proportions at a temperature between about 275 C. and 300 C. for a period of about 7 to 15 hours.

2. The process of preserving rubber which comprises incorporating therein a composite product obtained by causing to react in a closed vessel at a temperature between about 275 and 300 C. for a period of about 7 to 15 hours a primary aromatic amine with a saturated aliphatic hydrocarbon alcohol in approximately molar proportions.

3. The process of preserving rubber which comprises incorporating therein a composite product obtained by causing to react in a closed vessel at a temperature between about 275 and 300 C. for a period of 7 to 15 hours, approximately molecular proportions of a primary aromatic amine and a saturated aliphatic hydrocarbon alcohol in the presence of a condensation catalyst and removing the more volatile portions of the reaction mass.

4. The process of preserving rubber which comprises vulcanizin-g the same in the presence of a composite product obtainable by causing a primary amine of the benzene and naphthalene series to react with a saturated monohydric aliphatichydrocarbon alcohol in approximately molar proportions at a temperature between about 275 C. and 300 C. for a period of about 7 to 15 hours.

5. The process of preserving rubber which.

comprises vulcanizing the same in the presence of a composite product obtainable by causing to react in approximately molecular portions a primary amine of the benzene and naphthalene series and a saturated monohydrio aliphatic hydrocarbon alcohol having at least two carbon atoms, at a temperature between about 275 C. and 300 C. for a period of about 7 to 15 hours.

6. The process of preserving rubber which comprises vulcanizing the same in the presence of a composite product obtained by causing to react in approximately molecular proportions a primary amine of the benzene and naphthalene series and a straight chain saturated monohydric hydrocarbon alcohol at a temperature be-' tween about 275 C. and 300 C. for a period of about 7 to 15 hours.

7. The process of preserving rubber which comprises vulcanizing the same in the presence of a composite product obtainable by causing a primary aromatic amine to react'with a butyl alcohol in approximately molar proportions at a temperature between about 275 C. and 300 C. for a period of about 7 to 15 hours.

8. The process of preserving rubber which comprises vulcanizing the same in the presence of a composite product obtainable by reacting aniline and normal butyl alcohol in approximately molar proportions at a temperature between 275 and 300 C. for a'period of 7 to 15 hours.

9. The process of preserving rubber which comprises incorporating therein a composite product obtained by causing a primary aromatic amine to react with a saturated monohydric aliphatic hydrocarbon alcohol in the proportion of not more than one mol of amine to one mol of alcohol, at a temperature between about 275 C. and 300 C. for a period of about 7 to 15 hours.

10. The process of preserving rubber which comprises incorporating therein a composite product obtained by causing at least one primary aromatic amine to react with at least one saturated monohydric aliphatic hydrocarbon alcohol in approximately molecular proportions, at a temperature between about 275 C. and 300 C. for a period of about 7 to 15 hours.

11. An age-resisting rubber composition comprising rubber and a composite product obtained by causing a primary aromatic amine to react with a saturated monohydric aliphatic hydrocarbon alcohol in approximately molecular proportions, at a temperature between about 275 C. and 300 C. for a period of about 7 to 15 hours.

12. The process of preserving rubber which comprises treatingthe same with a composite product obtained by causing approximately molecular proportionsofa primary aromatic amine and a saturated monohydric aliphatic hydrocarbon alcohol to react at a temperature between about 275 and 300 C. for a period of about 7-15 hours in the presence of a catalyst.

13. The process of preserving rubber which comprises treating the same with a composite product obtained by causing a primary amine of the benzene and naphthalene series to react with a branched chain saturated monohydric aliphatic hydrocarbon alcohol in approximately molar proportions at a temperature between about 275 and 300 C. for a period of about 7-15 hours.

14. The process of preserving rubber which comprises treating the samewith a compo-site product obtained by causing a primary aromatic amine to react with a propyl alcohol in approximately molar proportions at a temperature between about 275 and 300 C. for a period of about 7-15 hours.

15. The process of preserving rubber which comprises treating thejsame with a composite product obtained by causing aniline to react with isopropyl alcohol in approximately molar proportions at a temperature between about 275 and 300 C. for a period of about 7-15 hours.

ALBERT M. CLIFFORD. 

